It’s too early to say whether Yahoo will screw up Tumblr—by making it ugly, by introducing terrible advertising, by obscuring its wealth of adult content, or by simply casting a pall over it so great that the site’s fickle younger users abandon it. It’s also too early to say whether Yahoo screwed up by buying Tumblr, whose explosive growth has slowed of late, according to Quantcast numbers. Or, more hopefully, maybe Yahoo made its first wildly successful acquisition and the two companies will grow together; Instagram, for example, has in many ways (though not all) been a model acquisition, with the majority of its users having signed up after its purchase by Facebook. The outcome may depend almost entirely on how happy Yahoo makes Karp. (Tumblr’s co-founder, Marco Arment,writes that “Tumblr is David, and David is Tumblr.”) Regardless, Yahoo’s acquisition further concentrates social networking in the hands of a few companies, leaving Twitter and Pinterest behind as the only big, independent social networks of their ilk aside from Facebook.
—Matt Buchanan on Yahoo’s acquisition of Tumblr: http://nyr.kr/10JTYog